Known model railroad locomotives, particularly model diesel-electric locomotives, are generally provided with powered trucks which serve as a collector for electricity running through a model railroad track. The locomotives are powered by small electric motors which are mechanically connected to the wheels to drive the locomotive over the rails. The locomotives are generally provided with a pair of trucks, in the front and rear of the locomotive, although some locomotives may be constructed which include more than two powered trucks. Known models include trucks which are mounted for movement about two axis relative to the locomotive chassis. Movement of trucks about only two-axis is adequate if the rails over which the locomotive moves are carefully laid and do not have any irregularities therein. However, and particularly in the case of the smaller scale, such as N gauge (1/160th scale) and Z gauge (1/220th scale) equipment, very minor irregularities in the track can create operational problems for the locomotives when the locomotives are equipped only with what is referred to herein as two-axis trucks.
Model railroad track is usually constructed from a pair of spaced apart conductive rails, which are generally made of brass or a nickel-silver alloy, and which are mounted on plastic ties The ties are joined together in either a flexible or rigid configuration. The ties and rails may be secured to a roadbed, or the ties and the roadbed may be integrally formed. The rails are secured to the ties by molded plastic "spikes", which are somewhat flexible and allow irregularities, which are visually imperceptible, to be present in what appears to be even, level track. Additionally, where the track is provided with turnouts, crossovers, grade changes or banked curves, additional irregularities occur.
The existence of irregularities in the track surface presents problems in operation of the model locomotives in that if some of the wheels of the locomotive lose contact with the rail, the electrical connection between the wheels, and hence the locomotive, and the rails is degraded. Additionally, the ability of the locomotive to pull the cars of the train attached thereto is degraded because less pulling force is exerted when all of the wheels are not in positive contact with the rails.